Improvement in wrenches



l v A2 Sheets--Sheet 2. n.. MGFARLAND. f

, wrenches. N0.l57,968 Patented'ec.22,1874` FAR K PLA CE, N Y,

UNITED STATES PATENT OEEICE.

` DAVID MOFARLAND, OF WORCESTER, MASSACHUSETTS.

IMPROVEMENT IN WRENCHES.

Specification forming part of Letters Patent No. 157,968, dated December22, 1374; .application filed November 5, 1874.

To all whom it may concern Be it known that I, DAVID MGFAELAND, of thecity and county of Worcester and State of Massachusetts, have inventedcertain new and useful Improvements in Carriage-Wrenches; and I dohereby declare that the following is a full, clear, and exactdescription thereof, sufcient to enable those skilled in the art towhich this invention belongs to make and use the same, reference beinghad to the accompanying drawings, which form a part of thisspecification, andin which- Figure l represents a back view of myimproved carriage-Wrench. Fig. 2 represents a side View of the same, andFig. 8 represents a transverse section at line w x, Fig. 2. Figs. 4, 5,and 6 represent modifications in the construction of the rosettemechanism.

My invention consists in the employment of a set-screw, in combinationwith the movable jaw and its operating rosette or worm, for the purposeof setting back said worm against its rack, and thus, by forcing forwardthe jaw, cause it to firmly clamp or gripe the nut, so that when removedfrom the axle end or bolt the nut will not fall from the jaws of thewrench.V

In the drawings, A denotes the bar of the wrench, formed of metal,rounded at its lower part to serve as a handle, and having a headjaw,A', at its upper end, and a screw-rack, a., along its rear upper part. Bindicates a movable jaw, iitted to slide along the upper portion of thebar A, and provided with projecting ear-pieces b b', between which aworm or screw-cut rosette, C, is arranged, supported on a center pin, c,in such position as to mesh with the rack a, and when revolved to movethe jaw B along the bar A. D indicates a set-screw, arranged inconnection with the jaw B, for the purpose of setting back the worm Cagainst the rack a, and to thus force the jaw B forward with a morepowerful pressure than can be exerted with simply the worm or rosette Calone. Screw D is provided with a comparatively ne thread, and is in thepresent instance arranged through the ear b', with its end in positionto strike against the upper part of the worm G when said screwD isturned in. The worm C is made with a slight looseness or longitudinalplay between the ears b b', so that when the jaw B is moved forwardagainst the nut the worm C will crowd against the ear b', and leave asmall space between the worm and ear b. When the jaws are tightened onthe nut as iirmly as can conveniently be done by means of the worm C,the screw D can be turned in against the end of the worm C, and theforce of said screw thus eX- erted against the rack a causes the jaws AB to gripe the nut as a vise, so that when the nut is removed from thebolt or axle end it will be retained in the wrench. In this manner thegreasy nuts on carriage-axles can be removed and replaced without thenecessity of taking hold of the nuts with the hand, and withoutliability of dropping them upon the ground.

I do not confine myself` to the particular construction and arrangementof the screw D herein shown, as said screw may be varied in form, and bearranged in various positions to act against the worm or itssupporting-pin c,-

Vor, if desired, said pin c may be fitted with a screw-thread to the earb', and be provided with a shoulder to act upon and throw back the wormwhen the pin is turned in; or, again, a screw-wedge, cam, or equivalentdevice may be employed, the resultant action upon the worm and jaw beingthe same. I prefer, however, the construction herein shown.

The jaws A and B are preferably formed with angular depressed faces, soas to lit onto the corners of the nut, as indicated by dotted lines.(See Fig. l.) Tapering square-edged slots E and F are formed through thehandle of the bar, which render the part light, and serve as a wrenchfor small nuts, and a forkopening, H, is formed at the end of the handlefor similar use. The openings E, F, and H are made of proper size to fitthe various sizes of small nuts commonly used in the construction ofcarriages, and are of great convenience for tightening such nuts whenthey become loose by the jar and use of the carriage.

The vise griping -jaws A B are more espe- Acially designed for use inhandling the large nuts which retain the wheels upon their axles.

I am aware that wrenches have heretofore been made and used in which thesliding jaw is operated by a screw-rosette Working in a against the racka and forcing forward the mok formed upon the bar, and I do not hereinjaw, substantially as and for the purpose set make claim to suchfeature; but forth.

What I claim as neW and of my invention, and desire to secure by LettersPotent, is-

The combination7 With the jaw B and its operating Worm or rosette C, ofthe set-screw D,

DAVID MGFARLAND.

Witnesses GEO. C. TAFT, for the purpose of setting beek said Worm S. R.BARTON.

